Microphonic relay assembly



Oct. 23, 1934. 3 LYBARGER 1,977,830

MICROPHONIC RELAY AS SEMBLY Filed March 19, 1934 NTOR Patented Oct. 23, 1934 UNITED STATES PATENT OFFICE J Myers;

Application Math 19, 1934, Serial No. 716,255 5 Claims. (01; 1 79 171) This invention relates to telephonic hearing appliances, and more particularly to a microphonic relay assembly'devised for use in a portable ear-phone system of the type e'mployedby the deaf to increase their hearing.

It is the common practice to employ in such system microphonicrelays of the carbon granular type, whichfare a form ofrelay, as is well known in the art, in 'whicha quantity of carbon globules loosely disposed between a pair of vertically disposed conductor plates is utilized to control the flow'of a current therethrough in re sponse to the movement of one or both of such plates. There are chiefly two different kindsof these relays, as microphonic transmitters and microphonic amplifiers or boosters'as the latter are frequently called, and it is the latter of these toward which this invention is more particularly directed, although it'is not necessarily so limited.

As customarily constructedthese relays will function properly only when the plates thereof are maintained in a substantially vertical position. While a certain departure from suchposition is permissible depending on the particular construction'used, if they are tilted in excess thereof, as they frequently are when used in earphone systems in the manner previously con- A more particular objec'tis to provide a micro phonic amplifier and battery assembly-for use in a portable earphone system which is adapted to be normally worn 'by the user in such away that the amplifier ismaintained in the proper position for its most efiicient operation at all times. I l

Another object is to provide a unit of this nature which is simple and sturdy of construction, as well as relatively inexpensive to manufacture and exceptionally easy and'convenient to use.

These and other objects, as well as the'va'rio'us other novel features and advantages offsthe invention, will be apparent when the following detailed description is readin conjunction with the accompanying drawing of which Fig. 1 is a view partly in elevation and partly in section of a battery unit and microphonic amplifier assembly constructed in accordance with the invention;

Fig. 2 an end elevation of the same assembly; Fig. 3 a diagrammatic view of the carbon globules and associated conductor plates of an amplifier such as shown in Fig. 1, illustrating such parts when disposed at right angles to the horizontal or their most effective operating position; Fig. 4 a view similar to Fig. 2 but showing the conductor plates tilted above their horizontal diameter in excess of 45; Fig. 5 a'view indicating the position which one of the units of the type contemplated by the invention frequently assumes when being used; and Fig. 6 aschematic view ilustrating in full and dotted lines various positions in which the unit may be disposed in normal service. 4

Referring to Figs. 1 and 2 a microphonic booster relay of the type' contemplated by this invention is illustrated which comprises a cup-shaped openfaced housing 1 within which, adjacent the rear Wall thereof, there is arranged an electromagnet 2 of suitable design and construction. Directly in front of such magnet a flexible diaphragm 3 is provided which is held in place by a cover 4 threadably mounted on the open end of the housing 1. In the center of thisdiaphragm, adjacent the core 6 of the electromagnet 2 and operatively spacedtherefrom, an armature 5 is secured. On the opposite side of such diaphragm a carbon disc 7 is mounted, being arranged for movement in a recess 8 in the cover 4 and adapted to form a movable wall at the inner end, of a chamber 9 formed by an opening 11 inthe center of such cover. This chamberis utilized to house a quantity of carbon globules 12 which are arranged loosely therein and the cover which is made of dielectricrnaterial is made sufliciently thick to provide the proper space for such globules; while the space between the cover and disc '7 is made sufliciently small to prevent the globulesescaping between it and the cover. I

At the outer end of the opening 11 in the cover 4 there is provided a normally fixed carbon disc 14 which isremovably held in a recess 13 by springclip 15 to facilitate the assembly of the carbon globules; This clip 15-is also utilized as a terminal for a current-conducting circuit, not' s'ho'wn, which extends through the carbon globules 12 -'to the inner disc '7. Secured to a base support l6;on which the housing 1 is mounted on thebotto'm of this base there is mounted a pair of terminals "17 for connecting the booster to the cooperating terminals 20of a battery-or battery container 18. while on its top adjacent the relay 8. second set of terminals 21 is-provided for conveniently connecting the booster in an ear-phone circuit 22 as shown in Fig. 5. These terminals of course are suitably connected to the proper elements of the'booster and detailed description thereof is deemed unnecessary.

The difficulty encountered in the use of a booster or relay of this nature in an ear-phone circuit, as referred to hereinbefore, is-that the carbon globules 12; as shown in Fig. 4, fall away from one of the conductor plates '7 or 14 if the device is permitted to tilt about the horizontal diameter of such plates, and reduce the effectiveness of the instrument in substantiallythe same ratio that the area of contact between such elements,

is thereby reduced, and if tilted-too far the circuit is broken entirely rendering therelay come. pletely inoperative.

To eliminate this difficulty in accordance with this invention asupport 18'is provided for the relay which is adapted to be worn parallel with the front or back of the wearer's body and the relay nountedon such support; with its carbon granular engaging plates? and 14 disposed as shown in Fig. '1 at right angles .to'the body-engaging surfaces of this support. Consequently as most body movements are in the plane of the plates when so supported, the area of contact between them and the carbon globules is maintainedin substantially the proper position for maximum effectiveness in operation at all times independently of whatevergthe degree of body movementmaybe. As a furtherfeature of the invention thebattery employedfor operating the hearing system inwhich the booster is used is employed as the support; for the booster. Toward this end, the battery or battery. container on which the booster may be mounted as shown in Figs.;1 and 2 ismade in a'wafer-like manner and preferably so designedthat it can be cone veniently placed in a' persons pocket as shown in Fig. 5 or attached to the frontqof his or her clothing, being of course equipped with suitable Such a terminals 20 for receiving the booster. unit has the further advantage that itcan be laid on its side ona table or thelike in the most stable-position of rest whennot beingworn by- According to the provisions of the patent statutes, I have explainedthe principle and mode of operation of my invention,-and haveillustrated and described what I, now. consider to;- represent its best embodiment. -I-Iowever, I-desire to have it understood-that,within the scope of the 1p.- pended claims, the invention may be practiced otherwise than as specifically illustrated and described.

. Iclaim: j

, 1. In combination, a microphonic relay comprising an electromagnet, a pair of 'spaced relatively movable conductor plates disposed adjacent said magnet, anarmature disposed in the field of 7 said magnet-and connected to one of said plates for movement therewith, a quantity of granular current-conducting material loosely arranged between said plates tobe-infiuenced-by the movement thereof, a flat faced support for said relay adapted to be-wornbya person with the surface,

thereof bearing against thewearers body, and

means for mounting said relay on said support with said plates disposed at right angles to the said body-contacting face.

2. In combination, a microphonic relay comprising an electromagnet, a pair of spaced relatively movable parallelly disposed conductor plates arranged adjacent said magnet, an armature connected to one'of said plates for movement therewith in the field of said magnet, a quantity of granular current-conducting material loosely arranged between said plates, a support for said relay adapted to be worn by a person with a definite surface thereof bearing against the wearers body, and means for mounting said relay on said support in such a manner as to positively maintain 'said plates at right angles to the body-contacting surface of the support.

3. In combination, a microphonic relay comprising an electromagnet, a pair of spaced relaating terminals in said support adapted to receive,

said relay terminals and maintain said plates at right angles to the body-contacting face of said battery container.

4. In combination, a microphonic' amplifier comprising an electromagnet, a'pairof spaced relatively movable parallelly disposed conductor plates arranged adjacent; said magnet, an armature connected to one of said plates for movement therewith in the field of said magnet, a quantity ofgranular current-conducting material loosely arranged between said plates, a housing for said aforementioned relay elements, current-conducting terminals for said relay mounted on said housing, a battery adapted to be Worn by a person with a surface thereof definitely bearing against the wearers body, and circuit-making terminals in said battery for detachably receiving the terminals on said relay and mounting the conductor plates of said relay at right angles to'the bodye ccnta'cting surface of the battery. V a

5. In combination, a microphonic amplifier comprising anv .electromagnet, a pair of spaced relatively movable parallelly disposed conductor plates arranged adjacent saidmagnet, and armature connected to oneof saidplates for movement therewith in the field of said magnet, a quantity of granular carbon loosely arranged between said plates, a housing in which =saidrelay parts are 

